Separate Change Unknown

Separate Change Uknown

Connie had 13 marbles. She gave some to Juan. Now she has 5 marbles left. How many marbles did Connie give to Juan?

Direct Modeling:
(Separate to)
13 - ? = 5
13 - 8 = 5



Modeling:
(Separate From)
13 - 5 = ?
13 - 5 = 8


Modeling:
(Join to)
5 + ? = 13
5 + 8 = 13



Counting:
(Count down to)
13 - ? = 5

(Count down from)
13 - 5 = ?

(Count up to)
5 + ? = 13


Facts:

Student is unsure of the fact 13 - ? = 5.

Student knows that 10 - 5 = 5

The student the knows he needs to add 3 to the 5 (3 + 5), and finds that the answer is 8.